Wireless radio system optimization by persistent spectrum analysis

ABSTRACT

Apparatuses and methods for simultaneously operating as a wireless radio and monitoring the local frequency spectrum. For example, described herein are wireless radio devices that use a secondary receiver to monitor frequencies within the operating band and prevent or avoid interferers, including in particular half-IF interferers. The systems, devices, and methods described herein may adjust the intermediate frequency in a superheterodyne receiver to select an intermediate frequency that minimizes interference. In particular, described herein are apparatuses and methods that use a second receiver which is independent of the first receiver and may be connected to the same receiving antenna to monitor the geographically local frequency spectrum and may detect spurious interferers, allowing the primary receiver to adjust the intermediate frequency and avoid spurious interferes.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/918,349, filed on Oct. 20, 2015, titled “WIRELESS RADIO SYSTEMOPTIMIZATION BY PERSISTENT SPECTRUM ANALYSIS,” (now Publication No.US-2016-0112074-A1), which is a continuation of U.S. patent applicationSer. No. 14/511,823, filed on Oct. 10, 2014, titled “WIRELESS RADIOSYSTEM OPTIMIZATION BY PERSISTENT SPECTRUM ANALYSIS,” (now U.S. Pat. No.9,191,037), which claims priority to U.S. Provisional patent applicationNo. 61/890,073, filed on Oct. 11, 2013, and titled “SPURIOUS FREQUENCYELIMINATION IN RADIO SYSTEMS FOR LONG-RANGE HIGH-SPEED WIRELESSCOMMUNICATION,” and U.S. Provisional Patent Application No. 62/019,359,filed on Jun. 30, 2014, and titled “WIRELESS RADIO SYSTEM OPTIMIZATIONBY PERSISTENT SPECTRUM ANALYSIS,” each of which is herein incorporatedby reference in its entirety.

This patent application may be related to U.S. patent application Ser.No. 13/871,882 (now U.S. Pat. No. 9,398,636), filed on Apr. 26, 2013,which is a continuation of U.S. patent application Ser. No. 13/448,610(now U.S. Pat. No. 8,467,759), filed on Apr. 17, 2012, which is acontinuation of U.S. patent application Ser. No. 12/618,690 (now U.S.Pat. No. 8,219,059), filed on Nov. 13, 2009, each of which is hereinincorporated by reference in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD

Described herein are wireless communications systems and methods,including broadband wireless radios such as IEEE 802.11 radios thatindependently and continuously monitor the spectrum of the operatingband. In some variations, these radios are adapted to use the spectruminformation (either local or regional) to avoid spurious interferencefrom interferers, such as the half-IF frequency.

BACKGROUND

Wireless communication devices and wireless networks have proliferatedin recent years. This has resulted in region having differentelectromagnetic spectrum profiles. For example, in some regionsgeographic as well as population conditions have resulted in relativelycrowded local frequency spectra. Although both regulatory agencies (suchas the FCC in the United States) and manufacturers have attempted toregulate and minimize such crowding, it has proven difficult to optimizeand prevent interference across commercially relevant portions of theelectromagnetic spectrum. In particular, electromagnetic interference,from both natural and man-made sources, is difficult to predict and toavoid. Unfortunately, electromagnetic interference causes significantproblems for wireless devices and networks. Electromagnetic interferencecan arise from other communication devices even if those other devicesuse a different carrier frequency. For example, a cordless telephoneusing a first carrier frequency could generate electromagneticinterference that makes it difficult for a communication device using asecond carrier frequency to maintain connection to a local area network(LAN). Electromagnetic interference might also arise from electronicdevices other than communication devices (e.g., microwave ovens, etc.).

Determining the source of interference and/or preventing or avoiding ithas proven difficult. One reason for the challenge is that theinterference may be sporadic. Another reason is that device could bemobile, as could sources of interference.

Since electromagnetic interference can be highly local, and interferencein the electromagnetic spectrum seen by some devices may not be seen byother devices even in the same network, it would be helpful to be ableto monitor local interference at a wireless radio device, including atboth ends of link in a network, such as at an access point (AP) and atan end device (e.g., a customer provided equipment, or CPE). Inaddition, since electromagnetic “traffic” and interference may varygreatly over time, it would be helpful to monitor continuously.

As an example, a particular wireless communication device that operatesin compliance with an 802.11 protocol might be experiencing periodicproblems associated with electromagnetic interference. An analysis ofthe local frequency spectrum content of the operating band may be usedto optimize performance of the local device as well an entire network.Spectrum content can be determined by a spectrum analyzer, which canmonitor frequency domain.

Thus, there is a need for devices and systems, and particularly wirelessradio devices and systems, that provide both local monitoring of thefrequency spectrum of a broadly-defined operating band whileconcurrently (and in some cases independently) receiving andtransmitting wireless radio frequency signals.

In superheterodyne receivers there are known vulnerabilities or spuriousresponses which may interfere with signal transmission. There are manytypes spurious interference, including, for example, thehalf-intermediate frequency (or “half-IF”) response. In such receivercircuits, mixers typically translate a high input radio frequency (RF)to a lower intermediate frequency (IF). This process is known asdown-conversion utilizing the difference term between a mixer's RF inputand a local oscillator input (LO) for low-side injection (LO frequency<RF frequency) or the difference term between the mixer's LO and RF forhigh-side injection. This down conversion process can be described bythe following equation: f_(IF)=±f_(RF)±f_(LO), where f_(IF) is theintermediate frequency at the mixer's output port, f_(RF) is any RFsignal applied to the mixer's RF input port, and f_(LO) is the localoscillator signal applied to the mixer's LO input port.

Ideally, the mixer output signal amplitude and phase are proportional tothe input signal's amplitude and phase and independent of the LO signalcharacteristics. Under this assumption, the amplitude response of themixer is linear for the RF input and is independent of the LO input.However, mixer nonlinearities may produce undesired mixing productscalled spurious responses, which are caused by undesired signalsreaching the mixer's RF input port and producing a response at the IFfrequency. The signals reaching the RF input port do not necessarilyhave to fall into the desired RF band to be troublesome. Many of thesesignals are sufficiently high in power level that the RF filterspreceding the mixer don't provide enough selectivity (e.g., rejection)to keep them from causing additional spurious responses. When theyinterfere with the desired IF frequency, the mixing mechanism can bedescribed by: f_(IF)=±m*f_(RF)±n*f_(LO). Note that m and n are integerharmonics of both the RF and LO frequencies that mix to create numerouscombinations of spurious products. The amplitude of these spuriouscomponents typically decreases as the value of m or n increases.

Knowing the desired RF frequency range, frequency planning is used tocarefully select the IF and resulting LO frequency selections to avoidspurious mixing products whenever possible. Filters are typically usedto reject out-of-band RF signals that might cause in-band IF responses.IF filter selectivity following the mixer is specified to pass only thedesired frequencies thereby filtering the spurious response signalsahead of the final detector. However, spurious responses that appearwithin the IF band will not be attenuated by the IF filter.

The half-IF spurious response is a particularly troublesome 2nd-orderspurious response, which may be defined for the mixer indices of (m=2,n=−2) for low-side injection and (m=−2, n=2) for high-side injection.For low-side injection, the input frequency that creates the half-IFspurious response is located below the desired RF frequency by an amountf_(IF)/2 from the desired RF input frequency.

The half-IF frequency represents a frequency where interference will beconverted to the IF frequency just like the desired receiver signal, butat a reduced efficiency. Unlike the image which is relatively easy tofilter out due to the large frequency difference from the desiredsignal, or signals that may cause blocking (which require very largesignals), the half-IF response can significantly impact achievableperformance. Other spurious responses may be found at other frequencieswithin the transmission bandwidth. In order to make a broadband wirelessradio device more selective, described herein are superheterodynereceivers that may mitigate the vulnerabilities/side-effects describedabove. In particular, described herein are devices and mechanisms thatalter the intermediate frequency based on the detected or predicteddistractors (e.g., spurious responses) at predetermined frequencies,including in particular the half-IF spurious response. This mechanism ofdynamically changing the frequency plan in response to actualinterference to avoid predictable spurious is applicable to otherspurious vulnerabilities as well as the half-IF frequency (e.g.,adjacent channel interference, 2×2 spurious responses, and otherinterferers).

SUMMARY OF THE DISCLOSURE

Described herein are wireless radio apparatuses (devices and systems)that include integrated spectrum analyzers. For example, describedherein are devices and systems that include a first wireless radioreceiver and transmitter (or transceiver) that operates in parallel witha second receiver; the second receiver may be configured as a spectrumanalyzer, and continuously scans the operating band. Thus, in any of thedevices described herein, the spectrum analyzer portion and the firstreceiver may be operated concurrently and independently of each other.Information on the spectrum that comes from monitoring the operatingband may be stored, analyzed and/or transmitted by a processor that isassociated with the spectrum analyzer, referred to herein as a spectrumprocessor. The spectrum information may be encrypted and may betransmitted to one or more remote processors (including servers) usingthe transmitter (Tx) that is used for normal operation of the wirelessradio, or the spectrum analyzer may include a dedicated transmitter (ortransceiver).

For example, described herein are wireless radio devices that areconfigured to wireles sly receive and transmit radio frequency signalsin an operating band and have an integrated spectrum analyzer. Thespectrum analyzer may be configured to operate continuously orcontinuously or constantly. For example, the spectrum analyzer may beadapted to constantly scan an operating band, and after one or more(predetermined) scan, may pause before starting the next scan or sets ofscans. For example, a wireless radio device configured to wirelesslyreceive and transmit radio frequency signals in an operating band havingan integrated spectrum analyzer may include: an antenna (e.g., a receiveantenna); a first receiver coupled to the antenna by a first receivingpath for receiving a radio frequency signal within the operating bandfrom the antenna; a spectrum analyzer operating in parallel with thefirst receiving path, wherein the spectrum analyzer is configured tocontinuously scan through the operating band and collect spectruminformation on the operating band concurrent with the first receiverreceiving the radio frequency signal; and a spectrum processor coupledto the spectrum analyzer and configured to wireles sly transmit thespectrum information to a remote spectrum analysis unit.

The antenna may be for both receiving and transmission, or it may be adedicated receive antenna. Although the primary receiver (ortransceiver) may operate with the same antenna (and in parallel) as thereceiver adapted to operate as the spectrum analyzers, the spectrumanalyzer may use a separate (e.g., dedicated) antenna.

The general-purpose receiver of the device or system typically receivesradio frequency signals within an operating band, as described ingreater detail below, may operate in one or more channels and may beswitches between channels within the operating band. The spectrumanalyzer typically scans through all of the channels of the operatingband. In some variations, the spectrum analyzer may scan though a bandthat is larger than the operating band, for example, bracketing theoperating band on one or both sides of the spectrum.

A wireless radio device configured to wirelessly receive and transmitradio frequency signals in an operating band may include: an antenna; afirst receiver coupled to the antenna by a first receiving path forreceiving a radio frequency signal from the antenna; a second receivingpath in parallel with the first receiving path, the second receivingpath coupled to the antenna and connected to a spectrum analyzer,wherein the spectrum analyzer is configured to continuously scan theoperating band while the first receiver receives the radio frequencysignal and to record spectrum information on the operating band; and aspectrum processor coupled to the spectrum analyzer and configured toencode the spectrum information for transmission to a remote spectrumanalysis unit.

Any of these devices may also include a first transmitter coupled to theantenna for transmitting radio frequency signals from the antenna. Ahigh-selectivity receiver may also be included in the first receivingpath, and configured to select an operational frequency (e.g., channel)for the first receiver from within the operating band.

The first receiver may be part of a transceiver comprising both atransmitter and a receiver. In general, the first receiver may operateindependently of (and simultaneously with) the spectrum analyzer.

In general, the spectrum processor may be separate than a processor thatoperates/control operation of the primary receiver (and/or transmitterand/or transceiver). For example, the spectrum processor may beconfigured to store, transmit, and/or analyze the spectrum information,as well as control the scanning of the spectrum by the spectrum analyzer(secondary receiver). For example, a spectrum processor of a spectrumanalyzer may be configured to store spectrum information for latertransmission. In some variations the spectrum processor may beconfigured to prepare the spectrum information for storage and/ortransmission. For example, the spectrum processor may be configured tocompress, extract, or encode the spectrum information for storage and/ortransmission. For example, the spectrum processor may also attachadditional information, such as identifying information for the device(wireless radio device) including a unique identifier specific to thedevice, and/or information about the general type of the device (model,year, etc.), time/date information may also be bundled with the spectruminformation. The spectrum processor may therefore store the informationand transmit it either continuously or discretely. The spectrumprocessor may use a dedicated transmitter and/or it may use the primarytransmitter of the wireless radio device. For example, the spectruminformation may be encoded and passed for transmission by the device(e.g., to a remote server) in a manner that does not interrupt normaloperation of the wireless radio device (in the absence of the dedicatedtransmitter).

Also described herein are general methods of simultaneously monitoring afrequency spectrum of an operating band and transmitting and receivingwireless information within the operating band. Any of these methods maybe performed by the apparatuses (device and systems) described herein.For example, a method of simultaneously monitoring a frequency spectrumof an operating band and transmitting and receiving wireless informationwithin the operating band may include: receiving and transmitting radiofrequency signals within the operating band using a wireless radiodevice including an integrated spectrum analyzer; continuouslymonitoring the frequency spectrum of the operating band concurrentlywith receiving and transmitting the radio frequency signals using thespectrum analyzer of the wireless radio device; and transmittingspectrum information collected from the spectrum analyzer to a remotespectrum analysis unit.

Another method of simultaneously and independently monitoring afrequency spectrum of an operating band and transmitting and receivingwireless information within the operating band may include: receivingand transmitting a radio frequency signal within the operating bandusing a wireless radio device having an integrated spectrum analyzer;continuously monitoring the frequency spectrum of the operating band andencoding the spectrum information using the spectrum analyzer of thewireless radio device concurrently with receiving and transmitting theradio frequency signal within the operating band; and transmitting thespectrum information to a remote spectrum analysis unit.

As mentioned, in any of these methods, the spectrum information in thewireless radio device may be stored, for later analysis and/ortransmission. Any of the methods described herein may also includeencoding the spectrum information in the wireless radio device.

The primary receiver may operate completely or partially independent ofthe spectrum analyzer (e.g., a secondary receiver configured to operateas a spectrum analyzer). For example, receiving (and transmitting) radiofrequency signals may include operating a receiver, transmitter ortransceiver of the wireless radio device without input from the spectrumanalyzer. For example, in some variations the devices described hereinare adapted to provide local frequency spectrum information about thefrequency environment of the device to a remote spectrum analysisapparatus. However, as described below, in some variations informationabout certain specific frequencies may be used by the primary receiver(and/or transmitter) to modify the operation of the device.

For example in some variations a device having a primary receiver and asecondary receiver may be configured so that the secondary receiver(which may be configured as a spectrum analyzer) looks at specific(e.g., predetermined) frequencies in order to avoid interference. Inparticular, described herein are apparatuses and methods for wirelessbroadband radio reception that prevent or avoid interferers, includingin particular half-IF interferers. In general, described herein areapparatuses, including systems and devices, and methods that adjust theintermediate frequency in a superheterodyne receiver to select anintermediate frequency that minimizes interference at one or morepredetermined frequencies. In particular, described herein areapparatuses and methods that use a second receiver, which is independentof the first receiver, and may be connected to the same receivingantenna, to detect the frequency location(s) of spurious interferers,and select or adjust the intermediate frequency using this information.The predetermined location of the spurious interferer may be calculated(e.g., the half-IF frequency of the system) or it may be determinedempirically, by scanning or otherwise examining the bandwidth before orconcurrently with operating the receiver, e.g., using a second receiver,spectrum analyzer, or receiver configured as a spectrum analyzer.

For example, described herein are methods of controlling reception for awireless broadband radio by selecting between a plurality ofintermediate frequencies (IFs) to minimize interference at firstpredetermined frequency (such as the half-IF frequency interference).Any of these methods may include: receiving a radio frequency (RF)signal having a frequency f_(sg) in a first receive path having a mixerfor generating an intermediate frequency (IF) signal from the RF signalby mixing the RF signal with a local oscillation (LO) signal having alocal oscillation frequency f_(LO);, wherein the intermediate frequencyis initially set to a first intermediate frequency, f_(IF1); determiningan interference in the RF signal at the first predetermined frequency;and switching the intermediate frequency to a second intermediatefrequency, f_(IF2), and generating the IF signal from the RF signal atthe second intermediate frequency if the interference in the RF signalat the first predetermined frequency exceeds a threshold level. When thefirst predetermined frequency is the half-IF frequency it may correspondto the one-half of f_(IF1) (a half-IF1 frequency).

As mentioned above, the predetermined frequency may be the half-IFfrequency. Spurious interferers at other predetermined frequencies mayalso be avoided. As used herein, the first (or second, third, etc.)predetermined frequency is predetermined in that it is known ahead oftime by the receiver. It may be calculated from a current or proposed IF(e.g., the half-IF frequency) or it may be identified ahead of time byscanning the bandwidth (e.g., using a spectrum analyzer, receiveroperating as a spectrum analyzer, etc.). In particular, thepredetermined frequency may be determined by scanning the bandwidthusing an auxiliary receiver (which may also be referred to as amonitoring receiver) that is independent of the primary receiver. Ingeneral, the first or other predetermined frequencies may also bereferred to as spurious interferer frequencies. For example, the firstpredetermined frequency may be referred to as a first spuriousinterferer frequency; the frequency may or may not actual includespurious interference. In some variations the first predeterminedfrequency is a frequency in which it is likely that spuriousinterference will be present.

In any of these examples, generating the IF signal at the secondintermediate frequency may include modifying f_(LO) to shift the IF tof_(IF2).

Any of these methods may also include receiving the RF signal in awireless broadband radio comprising a first receiver having the firstreceive path and a second receiver having a second receive path, whereinthe first and second receivers are both coupled to the same receivingantenna configured to receive an RF band. The second receiver may be amonitoring receiver configured to scan the band for interferenceindependently of the first receiver. Either or both the first and secondreceivers may be 802.11 receivers.

In general, a second receiver (e.g., a monitoring receiver) may be usedas a backup or redundant channel. For example, switching theintermediate frequency to a second intermediate frequency may furthercomprise receiving the RF signal in a second receive path whileswitching the IF to f_(IF2) to prevent an interruption in data trafficduring switching.

Further, determining the interference in the RF signal at the firstpredetermined frequency (such as the half-IF1 frequency) may comprisemonitoring a band including the RF frequency and the first predeterminedfrequency (e.g., half-IF1) on a second receive path that is independentof the first receive path. In general, the method may also includedetermining an interference signal/level in the RF signal at a secondpredetermined frequency. For example, the second predetermined frequencymay be the one-half of f_(IF2) (a half-IF2 frequency).

The threshold for determining switching of the IF frequency (e.g., fromIF1 to IF2) may include a comparison between the energy in the RF bandat the first predetermined frequency (such as the half-IF frequency ofthe first IF, IF1) and energy in the RF band at the second predeterminedfrequency (such as the half-IF frequency of the second IF, IF2). Forexample, switching may comprise switching the intermediate frequency tothe second intermediate frequency and generating the IF signal from theRF signal at the second intermediate frequency if the interference inthe RF signal at the half-IF1 frequency is greater than the interferencein the RF signal at the half-IF2 frequency. In some variations, theswitch may be triggered if the interference in the first predeterminedfrequency is more than an offset (e.g. a predetermined offset) from theinterference at the second predetermined frequency; for example, themethod (or an apparatus implementing the method) may trigger switchingif the interference at the first predetermined frequency is more than 10dB greater than the interference at the second predetermined frequency.

Thus, in general, the method may include switching the intermediatefrequency from the second intermediate frequency back to the firstintermediate frequency if an interference in the RF signal at the secondpredetermined frequency exceeds a threshold level. For example, themethod may include switching the intermediate frequency from the secondintermediate frequency back to the first intermediate frequency if aninterference in the RF signal at the second predetermined frequencyexceeds the interference in the RF signal at the first predeterminedfrequency.

In any of the methods and apparatuses described herein, the IF may beswitched from an initial IF to a new IF that is slightly shiftedrelative the initial IF. The initial IF may be referred to as a “firstIF” and the new IF may be referred to as a “second IF” (or additionalIFs, e.g., third IF, fourth IF, fifth IF, etc.). The frequencies of thefirst IF (IF1) and second IF (IF2) may be slightly shifted relative toeach other. For example, the frequency of the second IF may be laterallyshifted relative to the first IF (e.g., the new IF may be shiftedrelative to the initial IF by between about 10 MHz and about 250 MHz,between about 20 MHz and 200 MHz, between about 40 MHz and 150 MHz,etc.). In some embodiments, the initial IF and the new IF may beselected to be sufficiently nearby to permit the same filters that areadapted for use with the initial IF to be used with the new (shifted)IF, e.g., shifting within the bandwidth of the filter of the apparatus,while still providing sufficiently different the first and secondpredetermined frequencies (e.g., the half-IF) to avoid a spuriousinterferer that may be at or near one of the predetermined frequencies.In some variations the methods and apparatuses may switch to a new(e.g., second) set of filters for use with the second IF (IF2). Forexample, switching the intermediate frequency to the second intermediatefrequency may comprise switching the intermediate frequency from thefirst intermediate frequency to an intermediate frequency that isbetween about 10 MHz and about 250 MHz from the first intermediatefrequency. One of skill in the art should understand that the terms“first IF” and “second IF” as used herein does not refer to cascading orusing an intermediate step-down in frequency that may be used duringsuperheterodying (e.g., converting from 150 MHz down to 10.7 MHz, thendown to 455 kHz before demodulating). In contrast, the first IF andsecond IF described herein typically refer to alternative configurationsof the IF, and may be referred to as “first configuration” and “secondconfiguration”.

Thus, the methods described herein may also include switching in thefirst receiving path from a first filter configured to operate at thefirst intermediate frequency to a second filter configured to operate atthe second intermediate frequency.

Interference in the RF band at a particular frequency (or frequencyrange) such as the half-IF1 or half-IF2 frequencies, may be determinedin any appropriate manner. For example, determining the interference inthe RF signal at a first predetermined frequency (including but notlimited to the half-IF1 frequency) may comprise determining an errorrate at the first predetermined frequency. In some variations, theinterference may be determined based on the signal strength (e.g.,energy) at the frequency or range of frequencies, and particularly thenon-signal energy at those frequencies.

Any of the methods of controlling reception for a wireless broadbandradio by selecting between a plurality of intermediate frequencies (IFs)to minimize a predetermined frequency interference may include all orsome of the steps such as: receiving a radio frequency (RF) signalhaving a frequency f_(sg) in a first receive path having a mixer forgenerating an intermediate frequency (IF) signal from the RF signal bymixing the RF signal with a local oscillation (LO) signal having a localoscillation frequency f_(LO);, wherein the intermediate frequency isinitially set to a first intermediate frequency, f_(IF1); determining aninterference in the RF signal at a first predetermined frequency;determining an interference in the RF signal at a second predeterminedfrequency; and switching the intermediate frequency to the secondintermediate frequency and generating the IF signal from the RF signalat the second intermediate frequency if the interference in the RFsignal at the first predetermined frequency exceeds the interference inthe RF signal at the second predetermined frequency by a thresholdamount. As mentioned, the first predetermined frequency may be anyappropriate predetermined spurious interferer frequency, including (butnot limited to) the half-IF frequency; for example, the firstpredetermined frequency may be one-half of f_(IF1) (a half-IF1frequency), and the second predetermined frequency may be one-half of asecond intermediate frequency, f_(IF2) (a half-IF2 frequency).

As mentioned above, determining an interference in the RF signal at thefirst predetermined frequency and determining the interference in the RFsignal at the second predetermined frequency may include monitoring aband including the RF frequency, the first predetermined frequency andthe second predetermined frequency on a second receive path that isindependent of the first receive path.

As mentioned above and in general, switching the IF frequency may alsoinclude adjusting the local oscillator based on the new IF. For example,generating the IF signal at the second intermediate frequency comprisesmodifying f_(LO) to shift the IF to f_(IF2).

Any of the methods and apparatuses described herein may be configuredfor operation with a second (e.g., monitoring) receiver that is alsoconnected to the same receiving antenna as the first receiver. Forexample, the method of operation may also include receiving the RFsignal in a wireless broadband radio comprising a first receiver havingthe first receive path and a second receiver having a second receivepath, wherein the first and second receivers are both coupled to thesame receiving antenna configured to receive an RF band. The secondreceiver may be a monitoring receiver configured to scan the band forinterference independently of the first receiver. Either or both thefirst and second receivers may be 802.11 receivers. Switching theintermediate frequency to a second intermediate frequency may furthercomprise receiving the RF signal in a second receive path whileswitching the IF to f_(IF2) to prevent an interruption in data trafficduring switching. Further, determining the interference in the RF signalat the predetermined frequency may comprises monitoring a band includingthe RF frequency and the predetermined frequency on a second receivepath that is independent of the first receive path.

Switching may comprise switching the intermediate frequency to thesecond intermediate frequency and generating the IF signal from the RFsignal at the second intermediate frequency if the interference in theRF signal at the first predetermined frequency is greater than theinterference in the RF signal at the second predetermined frequency byany amount; however, in some variations if the interference in the RFsignal at the half-IF1 is the same (or approximately the same) as theinterference at the second predetermined frequency, then the method orany of the apparatuses implementing the method may remain at IF2, andnot switch.

As already described, switching may comprise switching the intermediatefrequency to the second intermediate frequency and generating the IFsignal from the RF signal at the second intermediate frequency if theinterference in the RF signal at the first predetermined frequency isgreater than the interference in the RF signal at the secondpredetermined frequency by some predetermined amount (e.g., about 10dB).

Any of the methods (and/or apparatuses for implementing them) describedherein may also include switching the intermediate frequency from thesecond intermediate frequency back to the first intermediate frequency(or to a third IF) if the interference in the RF signal at the secondpredetermined frequency exceeds the interference in the RF signal at thefirst predetermined frequency (or the third frequency) by a secondthreshold. As before the threshold may be the same as for switching fromIF1 to IF2 (including simply that the interference at IF2>interferenceat IF1).

For example, the method may also include switching the intermediatefrequency from the second intermediate frequency back to the firstintermediate frequency if the interference in the RF signal at thehalf-IF2 frequency exceeds the interference in the RF signal at thehalf-IF1 frequency. As described above, switching the intermediatefrequency to the second intermediate frequency may comprise switchingthe intermediate frequency from the first intermediate frequency to anintermediate frequency that is between about 10 MHz and about 250 MHzfrom the first intermediate frequency.

Also as mentioned above, in general, the method (or an apparatusimplementing the method) may include switching in the first receivingpath from a first filter configured to operate at the first intermediatefrequency to a second filter configured to operate at the secondintermediate frequency. In other variations the same filter (or filterset) may be used with any of the intermediate frequencies selected(e.g., IF1, IF2 , etc.).

Also described herein are wireless broadband radio apparatuses adaptedto select between a plurality of intermediate frequencies (IFs) tominimize interference (and particularly spurious interference atspecific frequencies such as the half-IF interference). For example, anapparatus may include: a receiving antenna; a first receiver coupled tothe receiving antenna having a first receiving path for receiving aradio frequency (RF) signal having a frequency f_(sg); a mixer in thefirst receiving path configured to generate an intermediate frequency(IF) signal from the RF signal by mixing the RF signal with a localoscillation (LO) signal having a local oscillation frequency f_(LO); anda controller configured to determine if an interference in the RF signalat a first predetermined frequency (such as, but not limited to,one-half of f_(IF1), a half-IF1 frequency) exceeds a threshold, and toswitch the intermediate frequency to a second intermediate frequency,f_(IF2), if the interference at the first predetermined frequencyexceeds the threshold.

The radio frequency (RF) signal may have a frequency f_(sg) within aband (RF band) and the apparatus may further comprise a second receivercoupled to the receiving antenna, the second receiver configured tomonitor the band and to scan the band for interference independently ofthe first receiver.

In some variations the same filter (or filter sets) may be used by thereceiver for both IF1 and IF2; in other variations different filters (orfilter sets) may be used depending on the IF. For example, the firstreceiving path may comprise a first filter adapted for use with thefirst intermediate frequency and a second filter adapted for use withthe second intermediate frequency, wherein the controller is furtherconfigured to select the first or second filter based on theintermediate frequency.

Any of the apparatuses described herein may be configured to alsotransmit and may therefore include one or more (preferably 2)transmitters coupled to a transmit antenna.

In general, the controller (which may also be referred to as aprocessor, control processor or control block) may be configured to setf_(LO) based on the intermediate frequency, as mentioned above. Thecontroller may be configured to switch the intermediate frequency to thesecond intermediate frequency, f_(IF2), if the interference at the firstpredetermined frequency is greater than an interference at the secondpredetermined frequency. The controller may be configured to switch theintermediate frequency to the second intermediate frequency, f_(IF2), ifthe interference at the first predetermined frequency is greater thaninterference at a second predetermined frequency by some threshold value(e.g., 10 dB higher than interference at a second predeterminedfrequency).

As mentioned, the second intermediate frequency may be slightly offsetrelative to the first IF. For example, the second IF may be betweenabout 10 MHz and about 250 MHz (about 20 MHz and about 200 MHz, about 40MHz and about 150 MHz, etc.) from the first intermediate frequency.

The first (and in some variations, the second) receiver may be a 802.11receiver.

Any of the apparatuses may also include a second receiver coupled toreceive input from the first antenna, wherein the controller isconfigured to process received RF signals using the second receiverwhile switching the intermediate frequency to f_(IF2) to prevent aninterruption in data traffic during switching.

As mentioned, the controller may be configured to determine if theinterference in the RF signal at a first predetermined frequency (suchas the half-IF1 frequency) exceeds the threshold by comparing theinterference in the RF signal at the first predetermined frequency withan interference in the RF signal at a second predetermined frequency(e.g., in some variations one-half of f_(IF2), a half-IF2 frequency).The controller may be configured to determine if the interference in theRF signal at the first predetermined frequency exceeds the threshold bycomparing an error rate at the second predetermined frequency with thethreshold. In any of these variations, the threshold may not depend onthe error rate at a second (or other) frequency, but may be based on anabsolute threshold level.

Also described herein are wireless broadband radio apparatuses adaptedto select between a plurality of intermediate frequencies (IFs) tominimize interference, the apparatus comprising: a receiving antenna; afirst receiver coupled to the receiving antenna having a first receivingpath configured to receive a radio frequency (RF) signal having afrequency fsg within a band; a second receiver coupled to the receivingantenna configured to monitor the band and to scan the band forinterference independently of the first receiver; a mixer in the firstreceiving path configured to generate an intermediate frequency (IF)signal from the RF signal by mixing the RF signal with a localoscillation (LO) signal having a local oscillation frequency f_(LO); acontroller configured to receive input from the second receiver todetermine if an interference in the RF signal at a first predeterminedfrequency (e.g., one-half of f_(IF1), a half-IF1 frequency) exceeds athreshold, and to switch the intermediate frequency to a secondintermediate frequency, f_(IF2), when the interference in the RF signalat the first predetermined frequency exceeds the threshold.

In some variations, the first receiving path may comprises a firstfilter adapted for use with the first intermediate frequency and asecond filter adapted for use with the second intermediate frequency,wherein the controller is further configured to select the first orsecond filter based on the intermediate frequency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A schematically illustrates one example of a device having anintegrated spectrum analyzer for independently and continuouslymonitoring the operating band.

FIG. 1B schematically illustrates another example of a device having anintegrated spectrum analyzer for independently and continuouslymonitoring the operating band.

FIG. 1C is a schematic illustration of a wireless radio device includinga persistent spectrum analyzer operating in parallel with ahigh-selectivity receiver.

FIG. 2A is schematic diagrams showing one variation of a wirelessbroadband radio apparatus adapted to select between a plurality ofintermediate frequencies (IFs) to minimize interference, as describedherein.

FIGS. 2B and 2C show variations of wireless broadband radio apparatusesadapted to select between a plurality of intermediate frequencies (IFs)to minimize interference; FIG. 2B shows a device having two antenna; inFIG. 2C, the device has two parabolic antenna.

FIG. 3 is a schematic illustrating one variation of a wireless broadbandradio apparatus adapted to select between a plurality of intermediatefrequencies (IFs) to minimize interference, including a primary receiver(having a receiving path) and a secondary or monitoring receiver, withboth primary and secondary receivers connected to the same receivingantenna.

FIG. 4 is a schematic illustration of another variation of a wirelessbroadband radio apparatus adapted to select between a plurality ofintermediate frequencies (IFs) to minimize interference. In FIG. 4, thefirst receiving path (in the primary receiver) includes two filter sets;a first filter is matched to the first IF, and the second filter ismatched to the second IF. Switching between the first and second IFswill also switch the first receiver between the appropriate filters tomatch the IF.

FIG. 5 illustrates another schematic of a wireless broadband radioapparatus adapted to select between a plurality of intermediatefrequencies (IFs) to minimize interference. In this variation theapparatus is also optimized to reduce adjacent channel interference; ahigh-selectivity RF circuit is coupled between the antenna and a firstradio receiver. Either or both the first radio receiver and/or thehigh-selectivity RF circuit may be adapted as described herein to switchthe IF.

FIGS. 6A and 6B illustrate schematics of wireless broadband radioapparatus adapted to select between a plurality of intermediatefrequencies (IFs) to minimize interference. In FIG. 6A the apparatusincludes a secondary radio receiver that is adapted to monitor the RFband of interest. In FIG. 6B, the secondary radio receiver may also beconfigured to act as a receiver for receiving wireless data when thefirst receiver is switching or otherwise not available.

FIG. 7A is a frequency spectrum diagram for a radio channel showing aninterferer near two half-IF frequencies for a first IF and a second (oralternate) IF, respectively.

FIG. 7B illustrates a method of controlling reception for a wirelessbroadband radio by selecting between a plurality of intermediatefrequencies (IFs) to minimize a half-IF frequency interference.

FIGS. 8A and 8B illustrate a frequency spectrum diagram for a radiochannel and an adjacent channel desired band strong interferer.

DETAILED DESCRIPTION

In general, described herein are wireless radio apparatuses that includea first (primary) receiver and a second (secondary) receiver that areconnected in parallel, for example, to the same receiving antenna. Theprimary receiver may be a high-selectivity receiver, and may beconfigured to receive radio-frequency signals within an operatingfrequency band. The second receiver may be configured as a spectrumanalyzer, that analyzes all or a portion (e.g., at predeterminedfrequency locations) of the operating band. The secondary receivertypically operates simultaneously with the first receiver, and mayoperate continuously or periodically (e.g., at regular intervals) toscan the operating band or predetermined portions of the operating band.The second receiver may be controlled by a secondary processor, whichmay be configured as a spectrum processor for controlling operation ofthe secondary receiver as a spectrum analyzer.

For example, FIGS. 1A and 1B schematically illustrate two genericvariations of devices that include a primary receiver (or a receiverportion of a transmitter) that is used to receive wireless data andoperates at one or more frequency channels within an operating band;these devices also include a secondary receiver that, in conjunctionwith a secondary processor, simultaneously scans the frequency spectrumof the operating band.

In FIG. 1A, the device 101 includes an antenna 102 to which a primaryreceiver 108 is connected via a receiving path (line 112). The primaryreceiver 108 is connected to (and may be controlled by) a primaryprocessor 106 or controller. In some variations the receiver is part ofa transceiver. In some variations (not shown) a separate transmitter maybe connected to the processor 106 and/or the antenna 102. This ‘primary’pathway may operate to wirelessly communicate with one or more otherdevices and typically transmits and receives radio-frequency informationusing one or more channels that are part of an operating frequency band.In this example, a secondary receiver 124 is connected in parallel withthe primary receiver 108 to the same antenna 102 which is also connectedto a secondary processor 122. In some variations a separate antenna maybe used. In FIG. 1A, the secondary receiver 124 is configured as aspectrum analyzer 120, and the secondary processor 122 is configured asa spectrum processor 122. The spectrum processor can control thespectrum analyzer 120 and process spectrum information about thefrequency band (or specific, predetermined sub-portions of the frequencyband). In particular, the spectrum analyzers (e.g., the spectrumprocessor portion of the spectrum analyzer) may store (e.g., in a memory130), analyze, encode, and/or transmit the spectrum information.

For example, a spectrum processor may cause the secondary receiver toscan through the operating band (frequency band) collecting frequencyspectrum information, including process frequency information atspecific predetermined frequencies. In FIG. 1A the spectrum information(encoded or otherwise) may be transmitted (e.g., using the sharedantenna 102 or a dedicated spectrum analyzer antenna or anothersecondary antenna), stored, presented (e.g., displayed) or analyzed.

In use, there are many functions that may be performed by apparatusesincluding a primary receiver and a secondary receiver adapted to analyzethe local frequency spectrum of the apparatus. In some examples, such anapparatus may be used for simultaneously communicating wirelessly (e.g.,via the primary receiver, a primary transmitter and/or a primarytransceiver) and monitoring the local frequency spectrum over theoperating band. The frequency information may be collected, analyzed,stored and/or transmitted. Spectrum information (data) from the spectrumanalyzer may be processed by filtering or the like. A spectrum analyzermay process signals continuously, e.g., without consideration ofprotocol preambles or data coding as would be used in the primaryreceiver. Thus packet detection is not required. Frequency domaininformation may describe power versus frequency for the real andimaginary component.

Spectrum information may be encoded with additional information such asone or more of: temporal information (date/time the frequencyinformation was collected), location/position information (e.g., GPSinformation locating the device geographically), orientation information(e.g., direction orientation), device-identifying information (uniqueidentifiers for a particular device, information about the make/model ofthe device, lot number, etc.), or the like.

Any of the frequency information (including encoded information) may bestored and/or transmitted. For example, in FIG. 1A, the spectrumanalyzer is shown connected to the antenna so that it can betransmitted.

FIG. 1B is another example of a device including a spectrum analyzer 120connected in parallel to a primary receiver 108. In this example, theprimary receiver is also connected to a processor 106 along with aprimary transmitter 110. A second antenna 104 is used to transmit, whilea receiving antenna 102 is used for receiving wireless radio-frequencyinformation. In FIG. 1B, the same device may be transmitting andreceiving simultaneously, and at the same time monitoring (using thespectrum analyzer 120) the frequency spectrum of the operating band.

In both FIG. 1A and FIG. 1B, the spectrum analyzers may wirelesslytransmit spectrum information (encoded or not). The spectrum informationmay be transmitted by primary transmitter and/or directly by the antenna(e.g., in FIG. 1B, the transmission antenna), as indicated by the dashedlines in FIG. 1B.

As mentioned above, described herein are radio devices that include atleast two sets of radio receivers, where the first (primary) one of thereceivers may be configured to act as a wireless radio for receivingdata and the second receiver may be adapted to do persistent spectrumanalysis of the band that the first receiver is operating in. In somevariations, the device may modify the first receiver based oninformation from spectrum analysis. In some variations, the device doesnot modify the first receiver based on information from the spectrumanalysis. The device may be adapted to transmit information about thelocal radio frequency (RF) environment from the spectrum analyzer andreport this information to an aggregator (e.g., a remoteprocessor/server) that can combine this information with other frequencyspectrum information from other locations (or overlapping locations).This collected information may be used to optimize the network frequencychannel planning, for example.

Thus, described herein are apparatuses and methods that use a secondaryreceiver set, which may be independent of the first receiver set and maybe connected to the same receiving antenna or may have a separateantenna, and is configured as a spectrum analyzer. In the example, shownin FIG. 1C, a radio device that is configured as an 802.11 deviceoperating in the 5 GHz band and includes pair of receivers 111, 113. Oneof the receivers is adapted as a spectrum analysis receiver that iscontinuously sweeping the full 5 GHz band. In FIG. 1C, both receiversare connected to the same front-end, including an antenna adapted toreceive in the 5 GHz band 103 and pre-filtering, such as a low-noiseamplifier 105. The first receiver 111 is a high-selectivity receiver(HSR) for processing data within the 5 GHz band. In parallel with thehigh-selectivity receiver 111, a second receiver 113 operates as aspectrum analyzer to monitor the 5 GHz band used by the first receiver111. A wireless chipset 109 and processor 107 may be used by either orboth receivers. For example, an 802.11(n) 5 GHz radio may be used as aspectrum analyzer along with another (data) receiver (primary receiver111) as part of an 802.11ac radio. The 802.11(n) receiver may performpersistent spectrum analysis in the background as the other receiverreceives data.

The spectrum information may be used to modify or adjust the operationof a network that includes one or more of the devices described above.In particular, similar devices may all report back to a processor(aggregator) that can monitor the overall RF environment status of anetwork or of multiple networks. This information may be used, forexample, to optimize network, by optimizing frequency channel planningor other means, or for optimizing the positioning or operation ofindividual devices within the network.

In some variations, the devices having a primary receiver that is usedto receive wireless data and a secondary receiver connected in parallelwith the primary receiver that can act as part of a spectrum analyzermay be configured to optimize performance of the primary receiver bymonitoring specific frequencies in the frequency spectrum using thesecondary receiver operating as a frequency analyzer in order to avoidinterferers. For example, described herein are methods and apparatusesthat minimize interference by selecting between a plurality ofintermediate frequencies (IFs) using the secondary receiver to controlselection. In particular, the methods and apparatuses described hereinmay be useful to reduce or eliminate the problem of spuriousinterferers.

Spurious interferes may be at specific, e.g., predetermined,frequencies. For example, the spurious interferer may be half-IFinterferences. Any of the apparatuses or methods described herein mayutilize two (or more) receivers that both (or all) receive input from asingle receiving antenna. These receivers may be independent of eachother. In some variations the receivers may be configured nearlyidentically. In some variations the receivers may be configured to actredundantly. In some variations one of the receivers may be a primaryreceiver and one may be a secondary receiver. The secondary receiver maybe configured as a monitor, to monitor the desired band of the RFsignals (including monitoring as a spectrum analyzer).

As used herein the desired band may refer to the frequency band orspectrum where the specified service is permitted to operate. Forexample, for IEEE 802.11b systems, the “desired band” spectrum is thespectrum encompassing channels permitted by the IEEE 802.11b radiostandard. For the U.S. this spectrum includes the 11 channels locatedwithin the band 2412 MHz to 2462 MHz. IEEE 802.11 systems may alsooperate in other bands such as 5.0 GHz frequency band. The desired bandspectrum is also referred to as the in-band spectrum. A filter thatfilters the desired band spectrum may be referred to as a “band selectfilter”. “Frequency band” or “frequency spectrum” may be usedinterchangeable, and these terms may also have the same meaning as theterm “band” or “spectrum”. The phrase out-of-band spectrum may refer tothe frequency band or spectrum outside of the desired band spectrum. ForIEEE 802.11 systems operating in the 2.4 GHz band, the “out-of-band”spectrum encompasses frequencies outside of the 2.4 GHz frequency range.A typical out-of-band filter may filter frequencies outside thefrequency band of 2400 MHz and 2484 MHz.

The phrase “desired channel” may refer to the frequency band or spectrumwithin the desired band spectrum where a specific channel may operate.For IEEE 802.11n systems, the desired channel bandwidth may be 5, 10,20, or 40 MHz. A filter that selects the desired channel bandwidth maybe referred to as a “channel select filter”. For IEEE 802.11b systemsoperating in the 2.4 GHz band, the channel assignments are within the2412 MHz to 2462 MHz frequency range and the channel bandwidth may be 5,10, 20 or 40 MHz. The term “radio signal” may refer to the radiofrequency signal received by the antenna of a radio receiver. The radiosignal may comprise the information signal and the interferer signals.The phrase “RF signal” may refer to a signal operating at radiofrequencies. An RF signal may be the radio signal or may be a signallocated in the high selectivity RF circuit. An “information signal” mayrefer to the portion of the RF signal that comprises the desired signalor information to be received. An “interferer signals” may refer to theportion of an RF signal that does not comprise any components of theinformation signal. The interferer signals may be desired band (in-band)or out-of-band. Desired band interferer signals may be located within adesired channel band, or may be located adjacent to a desired channelband. A strong interferer signal typically has a signal strength that isgreater than the information signal, and a lesser interferer has asignal strength that is less than the information signal. IEEE 802.11refers to the following standards: IEEE 802.11n (2.4 GHz and 5 GHzbands), IEEE 802.11b (2.4 GHz band), IEEE 802.11g (2.4 GHz band), andIEEE 802.11a (5 GHz band). There is also a public safety band availablein the U.S. operating with a 4.9 GHz band. Refer to appropriate IEEEstandard for further details. For example, IEEE Std 802.11-2007.

A superheterodyne (or “superhet”) architecture in a radio receiver mayprovide superior performance, especially to address adjacent channelinterference (ACT). Heterodyne means to mix two frequencies together toproduce a beat frequency, or the difference between the two frequencies.Amplitude modulation is an example of a heterodyne process where theinformation signal is mixed with the carrier to produce side bands.Side-bands occur at precisely the sum and difference frequencies (beatfrequencies) of the carrier and the information signal. Normally thebeat frequency associated with the lower side band is utilized in theradio system. The center frequency of the lower side-band is theintermediate frequency (IF).

When a radio system utilizes the lower side-band, a superheterodyneprocess is implemented. That is, the term superheterodyne may refer tocreating a beat frequency that is lower than the original signal. Hence,superheterodying mixes another frequency with the carrier frequency ofthe information signal so as to reduce the signal frequency prior toprocessing.

As an example, for IEEE 802.11b systems, the received carrierfrequencies include channels in the frequency band from 2412 MHz to 2462MHz. Hence, a received signal with a carrier of 2412 MHz may be mixedwith a synthesized reference clock of 2038 MHz to generate an IF of 374MHz.

One advantage of superheterodyning is an improvement in signal isolationby arithmetic selectivity, i.e., increasing the fractional bandwidth.This is the bandwidth of a device divided by its center frequency. Forexample, a device that has a bandwidth of 2 MHz with center frequency 10MHz may have a fractional bandwidth of 2/10, or 20%.

The ability to isolate signals, or reject unwanted ones, is a result ofthe receiver bandwidth. For example, the band-pass filter in the tuneris what isolates the desired signal from the adjacent ones. In reality,there are frequently sources that may interfere with the radio signal.The FCC makes frequency assignments that generally prevent thissituation. Depending on the application, one might have a need for verynarrow signal isolation. If the performance of your band-pass filterisn't sufficient to accomplish this, the performance may be improved bysuperheterodyning.

As discussed above in the background section, one undesirableconsequence of signal processing such as superheterodying is the half-IFspurious response, which has proven particularly difficult toameliorate. The general description of where this spurious signal occursis “half way between the desired Rx signal and the LO frequency”, or“half of the IF frequency offset from the desired Rx signal, in thedirection of the Local Oscillator frequency”.

Assuming “low side injection” where the LO frequency is below the Rx(receiver) frequency, a desired Rx frequency of 5800 MHz, and an IFfrequency of 1200 MHz, the half-IF vulnerability would be at 5200 MHz(5800-½ 1200). As discussed above, this is essentially anotherundesirable mixing product in the mixer. Two times the ½ IF frequencymixed with two times the local oscillator frequency results in the sameIF output frequency.

The traditional method of mitigating the half-IF vulnerability is to usea filter to significantly attenuate Rx signals at this vulnerablefrequency. This can be expensive, and can also limit the frequencycoverage range of a receiver to the point that it is undesirable.Assuming even ideal filters, this traditional method would limit thefrequency coverage to slightly less than one half of the IF frequency.So a receiver designed to receive 5.9 GHz as its upper frequency limitwith a 1.2 GHz IF could not be expected to perform below 5.3 GHz becausethe ½ IF vulnerability at 5.3 GHz when receiving 5.9 GHz would not beattenuated at all. The interference at that frequency would have thefull gain/response of the receiver and the only rejection would be thatinherent in the down converting mixer. Further, since ideal band passfilters are not available, this frequency coverage range limitation inpractice is more severe; the pass band of the filter must be reduced toallow some acceptable level of attenuation at these half-IF frequencyoffsets from the pass band.

The proposed methods and apparatuses described herein are a compromisebetween the strict traditional method relying strictly on filtering, andone that assumes that while interference can be debilitating, theprobability of having significant interference at more than one“half-IF” type frequency offset at the same time is unlikely. Thismethod does not eliminate the expectation of brute force filtering ofthe ½ IF frequency, but may lessen the impact if interference isexperienced due to insufficient filtering.

In general, described herein are methods and apparatus using an “agile”IF frequency that may be shifted or changed. The IF frequency may becontinuously tuned in some variations, or two or more discrete IFfrequencies may be chosen and selected between; IF frequencies maybeselected based on the availability of filters so that if interference isexperienced when using one IF configuration, the configuration can bechanged and the probability of equal interference at the new vulnerablefrequency would be low.

The switching of the IF in the apparatus and methods as described hereinmay be guided by an analysis of the band of interest. This analysis maybe performed concurrently with the reception of the RF signal(s), andmay be ongoing. In particular, the systems described herein may includea second, independent, receiver that is adapted to monitor the desiredband. For example, FIGS. 2A-2C illustrate different variations ofapparatuses that include a separate receiver. FIG. 2A shows an overallschematic illustration of an apparatus having a single receiving antenna202 and two (or more) independent receivers 208, 208′. Each receiver mayhave one or more receiving chains. In FIG. 2A, the apparatus alsoincludes a transmitting antenna 204 and a plurality of transmitters 210,210′ (which may also be independent). A controller/processor 206 may beincluded. The controller/processor may be configured to switch the IFbased on information about the interference at particular frequencies(e.g., half-IF frequencies).

FIGS. 2B and 2C illustrate wireless broadband radio apparatuses that maybe adapted to select between a plurality of intermediate frequencies(IFs) to minimize spurious interference. FIG. 2B shows the outside of anapparatus having two antennas; this variation the apparatus is a 5 GHz(or alternatively a 2.4 GHz) RF radio with two external antennas thatsupports 802.11n MIMO. In the variation shown in FIG. 2C the apparatusincludes two parabolic antennas; a cover (radome) has been removed toshow the two antennas 202, 204. In this example, the apparatus isconfigured as a 5 GHz apparatus that includes a transmit antenna 204 anda receive antenna 202. The receive antenna is connected directly to tworeceivers (receiver circuitry). The first receiver is a primary receiverand the second receiver is a secondary, or monitoring, receiver. Aprocessor/controller is also included and may communicate with both. Theprocessor/controller may decide, based on information provided by themonitoring receiver about interference at specific frequencies, whichmay be known a priori or determined on the fly, whether to switch the IFof the apparatus when receiving information (data) from the receiveantenna. The frequency (or in some variations frequencies) of thespurious interferer may be provided to the processor/controller (andthus be predetermined). For example, the monitoring receiver maydetermine the frequency of a spurious interferer at a first and/orsecond predetermined frequency location. For example, the monitoringreceiver may determine the interference at each of the half-IFfrequencies for a first IF (IF1, which can also be denoted herein asf_(IF1)) and a second IF (IF2, which can also be denoted herein asf_(IF2)), and this information may be sent to the processor/controllerto determine if the IF should be switched from the first IF (IF1) to thesecond IF (IF2), for example, if the interference at the half-IF2 isless than the interference at the half-IF1 frequency.

FIG. 3 illustrates one variation of an apparatus configured to switch oradjust IFs in order to avoid or minimize interferers in a desired RFband, and particularly half-IF interference. In FIG. 3, the apparatusincludes a single receive antenna 301 that is connected to each of tworeceivers, including a first receiver 303 and a second receiver 305,configured as a monitoring receiver. The apparatus also includes aprocessor or controller (processor/controller) 307. In this example, theapparatus may analyze, in real time, the RF band using the monitoringreceiver 305. The processor/controller 307, which may be part of a moregeneral processor and/or controller and encompasses both hardware,software and firmware, may determine if the IF should be switched basedon the interference in the band. For example, the controller/processormay determine that there is more interference (e.g., a stronginterferer) near the half-IF frequency at a first IF (IF1) compared tothe interference at a half-IF (IF2) frequency and therefore theapparatus may switch the IF from IF1 to IF2 (or vice versa, depending onthe interference profile). In general, the processor/controller 307 mayswitch the intermediate frequency (IF) based on the interference profileof the band, including specifically the half-IF frequencies. Theinterference profile may include the time duration, frequency (dutycycle/rate of occurrence), etc. The processor/controller 307 may beconfigured to adjust the IF, and may also adjust the local oscillator toaccommodate the new IF. Thus, the local oscillator 311 may be aprogrammable local oscillator that is configured to provide anappropriate LO based on the radio (receiver) tuning and on the set IF.

The first receiver 303 in FIG. 3 may be generally set up as asuperheterodyne receiver, and may include typical components, includingamplification 321, 323, filtering 327, a demodulator 329, and any othercomponent as appropriate. In FIG. 3, the filter(s) 327 may be chosen asappropriate over a range of IFs, such as IF1 and IF2, so that if theprocessor/controller switches the IF based on a detected interference(e.g., a half-IF interference), the same filter(s) may be used. In othervariations, as described in FIG. 4, the filter (filter sets) may beswitched as the IF is switched. The first receiver may be connected to,and may receive input from, the processor/controller 307, to switch theIF, including adjusting the IF and adjusting the LO (programmable and/oradjustable LO 311).

FIG. 4 illustrates a schematic of another example of a wirelessbroadband radio that is adapted to select between a plurality ofintermediate frequencies (IFs) to minimize the impact of a spuriousinterferer frequency (such as a half-IF) interference. In this example,as in FIG. 3, the same antenna (Rx antenna 401) is connected to tworeceivers. The first (“primary”) receiver 403 includes appropriatesuperheterodyne circuitry (e.g., filters 427, 428, amplification 421,423, mixer 437, demodulator(s) 429, and local/programmable oscillator411). As discussed above, the second receiver 405 may scan the band, andmay therefore be configured as a monitoring receiver. The monitoringreceiver may generally detect interferers, and provide this information(e.g., frequency location) to the processor/controller to modifyactivity of the radio, for example, by modifying the first receiver. Forexample, the monitoring receiver 405 may examine the energy at thehalf-IF frequencies for the various selectable intermediate frequencies(IF1, IF2, etc.), to determine if there is an interferer at thesefrequencies. The processor/controller may then switch between thepossible IFs based on the information provided by the monitoringreceiver, and set the IF of the receiver 403 accordingly.

In FIG. 4, the primary receiver 403 may include a receive path that canbe switched 431 by the processor/controller 407 depending on the IF.Although in general different IFs may be only slightly shifted relativeto each other (e.g., IF2 may be within 20-250 MHz of IF1, or betweenabout 20 MHz to about 150 MHz of IF1, etc.), the filter used by thesuperheterodyne receiver may be selected based on the IF being used(e.g., IF1, IF2, etc.). Thus, in the receive path, theprocessor/controller 407 may select between a first IF circuit 435within the primary receiver, adapted for use when the IF correspond toIF1, and a second IF circuit 437 within the primary receiver, adaptedfor use when the IF corresponds to IF2. The filters 427, 428 may share acommon amp 423 and demodulator 429 in the receive path or the first IFcircuit and the second IF circuit may include a specific demodulator andamplifier (not shown) adapted for use at IF1 and IF2, respectively. Theprocessor/controller 407 may switch/select which IF is applied, andwhich IF circuit to use (1^(st) IF circuit 435 or 2^(nd) IF circuit437), as appropriate.

In operation, the processor/controller 407 may, in an ongoing manner,receive information from the monitoring receiver 405 about the RF bandincluding the signal (region of interest) and any other surroundingregions, and may control the primary receiver (and in some variations,the secondary receiver) in order to avoid interferers that may reducethe effectiveness of the radio. In the examples of FIGS. 3 and 4, theprocessor/controller 407 may adjust the IF of the radio, includingadjusting the local oscillator, filters, and the like, so that the radioswitches the intermediate frequency to an intermediate frequencyproviding enhanced performance, e.g., to avoid interferers such as thehalf-IF spurious response. Although FIGS. 3 and 4 show only two IFs (IF1and IF2), three or more IFs may be used, and selected between by theprocessor/controller in the same manner. Additional circuitry (e.g.,filters) appropriate to each IF may be included.

In FIGS. 3 and 4, the apparatus adjusts the IF of one (or both inapparatuses in which the secondary receiver may also be used to receiveand process data, for example, during switching) of the receivers withinthe superheterodyne circuitry. In any of these variations, the IF may oralternatively be adjusted in any pre-processing circuits, as describedin apparatuses including adjacent channel optimization receivers, asdescribed in U.S. Pat. No. 8,219,059. In these apparatuses, the receiverincludes a high-selectivity RF circuit that processes the signal(down-converting, filtering, and up-converting) to remove interferersthat are near but not within a desired bandwidth. FIG. 5 illustrates avariation of a high-selectivity circuit 508 that is connected to asecond (monitoring) receiver through a processor/controller 507 that canselect the IF for the high-selectivity circuit. In some variations theprocessor/controller may also communicate 541 with the primary receiverand set the IF within the receiver (as shown in FIGS. 3 and 4, above).

FIGS. 6A and 6B schematically illustrate wireless broadband radios thatmay select between a plurality of intermediate frequencies (IFs) tominimize a half-IF frequency interference. As mentioned above, any ofthe apparatuses and methods described herein may include multiple(independent) receivers that communicate with the same receivingantenna. One of these receivers may be designated as a primary receiverand the other as a secondary receiver; in some variations the tworeceivers may be interchangeable, while in other variations one receivermay be a dedicated monitoring receiver. For example, in FIG. 6A, theprimary receiver is configured as an 802.11 receiver, and the secondaryreceiver is a monitoring receiver. A control (e.g.,“processor/controller” or IF controller) 604 receives input from themonitoring receiver 605, and may adjust the primary receiver 603, e.g.,selecting the IF of the primary receiver. In the variation shown in FIG.6B, both the primary receiver 603′ and the secondary receiver 605′ arebe configured as an 802.11 receiver; the control 604′ may communicatewith both the primary and secondary receiver. The primary and secondaryreceivers may switch between monitoring and data processing; thisswitching may be controlled by the controller 603′. In the variation ofFIG. 6B, each receiver may be adapted to operate at a slightly differentIF (or more than one IF).

Any of the apparatuses described herein may be configured to reduce orminimize interference by taking advantage of a second receiver thatoperates in parallel with a primary receiver. By concurrently andactively monitoring the RF band, the second receiver may provideinformation allowing the apparatus to avoid, minimize or eliminateinterferers. In particular, the apparatus may be specifically configuredto avoid spurious interferers at the half-IF. This is illustrated, forexample, in FIG. 7A. FIG. 7A shows a frequency spectrum diagramincluding a radio channel of interest. FIG. 7A also indicates thelocation of the desired signal 701, and the locations of each of twohalf-IF positions for two different IFs (e.g., configuration #1 at IF1and configuration #2 at IF2). Although the desired signal 701 iswell-separated from the interferer identified 705, the interferer isvery near to the half-IF location of the first configuration (IF1),which would result in a spurious signal due to the half-IF if the firstIF (configuration #1) were used. In this example, the band may bemonitored as shown in FIG. 7A by a second (e.g., monitoring) receiverthat can determine the location of interferers, including monitoringsensitive locations or regions of the spectrum (e.g., ½ IF1, ½ IF2,locations of filters etc.). This information may be passed on to aprocessor/controller (e.g., IF controller) and used to set or switch theIntermediate Frequency (IF).

In the FIG. 7A, some interference is experienced at the half-IFvulnerability for first configuration (configuration #1) 707. There issome attenuation in the RF band pass filter at this frequency, but notvery much. If the IF configuration were changed to the secondconfiguration (“config #2”) which corresponds to a half-IF at 709, theinterference would be avoided entirely. FIG. 7A indicates the vulnerablefrequency ranges 707, 709 for each configuration when configured toreceive “desired signal”.

Thus, in some variations, a method or apparatus incorporating the methodmay use two IF frequencies that are relatively close. For example, afirst and second IF that are within 250 MHz or less, where filters thatprovide close-in selectivity are available. The method and/or apparatusmay adaptively select between these two IF frequencies to dodgeinterference. This may not only result in reduced interferencesusceptibility, but may also offer a wider frequency coverage rangewithout additional substantial filtering requirements, or withoutneeding complex and expensive filters.

In general, the method switches the IF of an apparatus based on theamount of interference in a predetermined location (e.g., at thehalf-IF). The system actively monitors a frequency region such as thehalf-IF frequency to determine if there is interference above athreshold and, if so, switches to another IF. In general, a thresholdmay be a predetermined value, or it may be based on comparison toanother region. For example a threshold may be the amount ofinterference at another frequency region, such as the half-IF at thealternate frequency (IF2). A system may toggle between a first IF (IF1)and a second IF (IF2) by comparing the amount of interference at each ofthese susceptible frequencies, choosing the IF having less interferenceat its half-IF frequency.

FIG. 7B illustrates an example of a method for controlling reception ofa wireless broadband radio by selecting between a plurality ofintermediate frequencies (IFs) to minimize half-IF frequencyinterference. In FIG. 7B, the method includes receiving a radiofrequency (RF) signal having a frequency f_(sg) in a first receive path751. The first receive path may have a mixer for generating anintermediate frequency (IF) signal from the RF signal by mixing the RFsignal with a local oscillation (LO) signal having a local oscillationfrequency f_(LO). The intermediate frequency may be initially set to afirst intermediate frequency (IF1), which may be referred to as the“current IF”. At the same time that the RF signal is received by thefirst receive path, a second receiver (connected to the same antenna)may independently determine interference in the RF signal, for example,by monitoring the RF band (spectrum). In particular, the second receivermay monitor the RF band to determine any interference at a frequencythat is one-half of IF1/f_(IF1) (a half-IF1 frequency) 753. In somevariations the second receiver may also determine the interference atthe half-IF frequency for a second (slightly shifted) IF, IF2, which isinitially a “new IF”. If the interference at the half-IF for the currentIF frequency is greater than a threshold 757 (e.g., greater than theinterference at the half-IF frequency of the new IF), then the IF of thereceiver may be switched to the new IF, by setting the current IF to thenew IF (conversely the new IF now becomes the old current IF, allowingthe steps to repeat to switch back if the interference profiles change)759. Thereafter, the new “current” IF (e.g., IF2) may be used togenerate an IF signal for the RF signal at the “new” current IF if theinterference in the RF signal at the half-IF1 frequency exceeded athreshold level. While the interference at the half-IF frequency for thecurrent IF is below the threshold, the IF may stay the same 760.Monitoring and controlling the IF may be ongoing, while the firstreceiver (receiver 1) continues to process received data 755 usingwhatever IF has been set.

For example, for a 5 GHz receiver, the IF may be changed dynamicallybetween 1200 and 1000 MHz (e.g., IF1=1200 MHz, IF2=1000 MHz), whichwould move the “vulnerable” (half-IF) frequency by 100 MHz. The scenarioshown in FIG. 7A may represent a worst case, e.g., the nearest“vulnerable” frequencies always occur when the receiver is configured toreceive the highest channels in the frequency range when the localoscillator injection is on the low side, so the interference andvulnerable regions are shown on the slope of the RF band pass filterresponse where the attenuation is a compromise.

In one example, a 5.8 GHz receive frequency is used with an apparatushaving an initial (IF2) IF of 1.2 GHz, using low side injection. Thelocal oscillator is initially set at 4.6 GHz (e.g., 5.8 GHz−1.2 GHz). Inthis mode of operation, the half-IF vulnerability is at 5.2 GHz (e.g.,5.8 GHz−1.2 GHz /2). One approach to avoid that spur of interference maybe to shift the IF frequency (either within the pass band of one IFfilter or to switch to a separate IF filters) to 1.0 GHz. In that case,to receive 5.8 GHz, the local oscillator would be tuned to 4.8 GHz (with1 GHz IF rather than 4.6 GHz with the 1.2 GHz IF). Switching in thismanner may avoid that half-IF spur. In this example, the monitoringreceiver may provide confirmation that the half-IF frequency at 1.0 GHzhas a lower interference than the 1.2 GHz. This is just one example ofshifting the IF. The implementation of the shifting may depend on thebandwidth of the channels; however in general, the shifting may avoidthe interference spur while making the smallest change in the IF. Also,in practice, the methods and apparatuses described herein may beimplemented as part of a MIMO system, using multiple (e.g., four live)receivers and antennas.

As mentioned above, the dual receivers described above, as well as themethods and apparatuses for avoiding the half-IF frequency, may be usedto help with adjacent channel optimization, enhancing the methods andsystems described, for example, in U.S. Pat. No. 8,219,059, previouslyincorporated by reference in its entirely. U.S. Pat. No. 8,219,059describes devices and methods for adjacent channel optimization.

In use, an auxiliary (secondary) receiver may be a fully independentreceiver (not affecting main or primary receiver). A secondary receivermay be exposed to the whole band, and may be used to detectinterference. As discussed above, it may be used to determineinterference at known frequencies such as the half-IF frequency, and mayprovide pass band tuning opportunities based on states of interference.As mentioned above, the additional receiver could also handle Rx trafficduring a configuration change of main Rx for filtering and/or switchingof the IF, or the like.

An adjacent channel optimized receiver as described in the '059 patentmay be modified to include two features; first a bandwidth/filteringselectivity that is known a priori (based on the channel bandwidth used)and a more adaptive implementation of “pass band tuning”. The “pass bandtuning” is an optional mode where the frequency conversion circuitryplaces the “desired” signal closer to one IF filter pass band edge thananother, in order to take advantage of the higher selectivity that thisaffords to interference to one side of the desired signal. The Pass BandTuning is demonstrated in FIG. 8 below.

In FIG. 8, pass-band tuning represents a compromise in that someadditional attenuation may be experienced or flatness of the frequencyresponse of the desired channel could be compromised. These areconsidered to be opportunistic improvements, a compromise in operatingperformance. In the '059 patent, the receiver/system may adaptively trythese pass-band tuning shifts and measure whether improvements wererealized. Although this process of “trial” may be effective, it may bemore efficient or robust to performing this step concurrently with asecond receiver, as it could be performed while operating the receiver.

Thus, in some variations, an apparatus having a high-selective RFcircuit as described in the '059 patent may include a monitoringreceiver that could independently (without impact to the main RX systemand data flow) scan the band for interference, collect statistics, andprovide informed decisions to the system as to best use the “highselectivity” features. In addition to using this receiver for optimallyusing pass band tuning, the monitoring receiver could also spot-checkfor half-IF spurious vulnerability and inform the system of threats asdiscussed above. This secondary receiver does not need to be a full802.11 receiver, but could be a simpler implementation used only forscanning for interference. A secondary (monitoring) receiver may be lesssensitive than a traditional receiver. For example, a monitoringreceiver may be a zero-IF receiver. The secondary receiver may have adifferent architecture than the primary receiver, which may not sufferfrom the same spurious responses/interference as the primary receiver.In some variations the monitoring receiver is a full 802.11 receiver;both the primary and secondary receiver may be full 802.11 receivers.

For example, FIGS. 8A and 8B illustrate the operation of ahigh-selectivity RF circuit, as described in the '059 patent. FIG. 8Aillustrates frequency spectrum 800, the frequency spectrum of radiosignal. Within the desired band spectrum is the spectrum for thepermitted carrier channels. For example, in FIG. 8A, there are 11 radioor carrier channels indicated, representing the 11 channels in the IEEE802.11b standard. The information signal is illustrated on FIG. 8A byspectrum 801 with the center frequency f_(c) of radio channel 3 andbandwidth BW. Also within the desired band spectrum is a stronginterferer 802 and lesser interferers 804.

High selectivity RF circuit performance may be further improved byshifting the IF, guided by a monitoring receiver as discussed above. Forexample, consider the situation illustrated in FIG. 8B with frequencyspectrum 900, wherein there are lesser interferers 804 and an additionalinterferer 904 that has slightly stronger signal power than lesserinterferers 804. Additional interferer 904 has a signal power ofapproximately −77 dBm and lesser interferers 804 have signal power ofapproximately −92 dBm. The IF may be shifted (pass band tuned) to aslightly higher or lower frequency in order to filter a desired bandinterferer signal. For example, referring to FIG. 8B, frequency spectrum900 illustrates that if the IF is shifted to a slightly lower frequency,then additional interferer 904 may be partially filtered from thedesired band. As shown in FIG. 8B, the IF is shifted from f_(c) tof_(shift), resulting in spectrum 903 being shifted to a lower frequencythan the spectrum 801 of the information signal. In this situation,additional interferer 904 is filtered such that its signal power isreduced from approximately −77 dBm to approximately −92 dBm.

One method of implementing such a pass band tuning is to have the radioreceiver determine if there are lesser interferers 804 or an additionalinterferer 904 in the desired band in close proximity of the skirts ofthe current channel, at either a higher frequency or lower frequency. Ifthis condition is determined to exist, then the apparatus may sendinformation on the control signal to shift the IF, and instruct thelocal oscillator (e.g., programmable local oscillator) to generate a newIF that is either slightly higher or slightly lower than the previouslyspecified IF frequency. The value that the IF may shift may varydepending on the specific design. As one example, pass band tuning mayshift the IF from 5% to 20% of the IF frequency.

The shifted IF may push a signal up against the edge of the “real”filter. Likely the “real” filter has a gradual roll-off. In this case,one may find that while the desired signal suffers some distortion dueto additional attenuation from the IF filter at the edge of the filter,there remains more benefit from the additional rejection of a strongerinterferer.

In any of the apparatus and methods described herein, in addition to notdisrupting the main receiver for spectrum monitoring tasks, theauxiliary (secondary or monitoring) receiver (if of similar type andcapability) could also take over data flow responsibilities brieflywhile the “high selectivity” receiver is reconfigured, thus providingless interruption in user traffic. The monitoring receiver would nothave the same level of selectivity (and may be less sensitive, making itless vulnerable to overload and useful for diagnosing interference), butmay be better than having a completely non-functional receiver for thebrief time that was needed to reconfigure. The auxiliary RX could alsobe used for redundancy with the primary receiver.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

As mentioned above, the methods and apparatuses described herein are notlimited to eliminating or reducing spurious interferers at a half-IFfrequency, but may be used to reduce or eliminate other (includingmultiple) predictable spurious interferers by dynamically changing thefrequency plan in response to actual interference at known frequenciesto avoid spurious interference at or near known frequencies or frequencyranges. Thus the apparatus and methods described herein are applicable,and may be readily adapted for use, to reduce or eliminate spuriousinterference at other vulnerable regions as well. For example, themethods and apparatuses described herein may be used to detect (e.g.,using a monitoring receiver) interference such as adjacent channelinterference, 2×2 spurious responses, and other interferers and shift oradjust the IF accordingly. For example, the apparatus and systemsdescribed herein may be used to examine the frequency spectrum using theauxiliary or monitoring receiver to select an intermediate frequencythat minimizes or eliminates spurious interference by looking forinterferers at predetermined locations based on two or more intermediatefrequencies.

In one example, the desired receiving frequency, Rx, is centered at 5.7GHz, and the intermediate frequency (f_(IF)) is initially 1.2 GHz. Aspurious interferer is located at 5.6 GHz (the interferer is 100 MHzlower than the desired receiving frequency). The f_(LO) is 4.5 GHz. Thespur (spurious interferer) has a RF harmonic (M) at −3 —dB (harmonic ofinterference) and a LO harmonic (N) at 4 —dB (LO harmonic). In the superheterodyne receiver, the f_(interference) is 1.2 GHz at the IF,resulting in the spur being located directly on the desired channel.However, as described above, if the intermediate frequency is shifted by10 MHz, to 1.21 GHz, the spur is displaced by 50 MHz from the desiredchannel (e.g., f_(LO) is 4.49 GHz, and the f_(interference) is 1.16 GHzat the IF). The interference converted up by the system is 5.65 GHz,with an offset of −0.05 GHz (e.g., 50 MHz below the desired signal).

Similarly, the spur may be avoided by shifting the IF in the otherdirection by the same amount, for example, by using an IF that is 1.19GHz or 10 MHz lower than the initial IF. In this example, the sameinterferer is instead shifted during super heterodyning so that f_(LO)is 4.51 GHz, and the f_(interference) is 1.24. The interference isconverted up by the system to 5.75 GHz. Thus, a 10 MHz shift in the IFin the other direction moved the interference to 50 MHz above thedesired signal.

This example illustrates how just shifting the IF 10 MHz can push aspurious response 50 MHz away from a desired channel (signal), and theshift can move up or down, depending on the IF chosen. This may aid indetermining which IF to apply. For example, the system may be configuredto determine which direction to shift the IF when weighing all otherconditions, including the locations of other signals, or evenlimitations of the hardware.

In this example, the change in the IF may be triggered when thefrequency of the spur would cause it to overlap or collide with adesired signal during the super heterodyning process. Thus, the decisionto shift the IF based on a predetermined frequency (e.g., a spur whosefrequency is determined, e.g., by the monitoring receiver) may be madein part by comparing the shift in frequency during super heterodyning,to determine if there is proximity or overlap with a desired signal.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, as used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements, these features/elements should not be limitedby these terms, unless the context indicates otherwise. These terms maybe used to distinguish one feature/element from another feature/element.Thus, a first feature/element discussed below could be termed a secondfeature/element, and similarly, a second feature/element discussed belowcould be termed a first feature/element without departing from theteachings of the present invention.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately,” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical rangerecited herein is intended to include all sub-ranges subsumed therein.Per M.P.E.P. § 2173.05(b), one of ordinary skill in the art would knowwhat is meant by “substantially equal”. For example, the phrase“substantially equal” or “substantially the same” in a statement such as“a fourth RF signal having substantially the same carrier frequency as afirst RF signal” may mean a radio receiver that receives either RFsignal may operate in an equivalent manner.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept, if more than one is, in fact, disclosed. Thus, althoughspecific embodiments have been illustrated and described herein, anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

What is claimed is:
 1. A wireless radio device configured to wirelesslyreceive and transmit radio frequency signals in an operating band, thedevice comprising: an antenna; a first receiver coupled to the antennaby a first receiving path for receiving a radio frequency signal withinthe operating band from the antenna; a spectrum analyzer operating inparallel with the first receiving path, wherein the spectrum analyzer isconfigured to continuously scan through the operating band and collectspectrum information on the operating band concurrent with the firstreceiver receiving the radio frequency signal; and a spectrum processorcoupled to the spectrum analyzer and configured to wirelessly transmitthe spectrum information and geographic location information to a remotespectrum analysis unit.
 2. The device of claim 1, further comprising atransmitter, wherein the spectrum processor is configured to sendinstructions to the transmitter for wireles sly transmitting thespectrum information and geographic location information to the remotespectrum analysis unit.
 3. The device of claim 1, wherein the firstreceiver is part of a transceiver, wherein the spectrum processor isconfigured to send instructions to the transceiver for wireles slytransmitting the spectrum information and geographic locationinformation to the remote spectrum analysis unit.
 4. The device of claim1, wherein the processor is configured to wirelessly transmitinformation identifying the wireless radio device.
 5. The device ofclaim 1, wherein the spectrum analyzer comprises a memory for storingthe spectrum information for later transmission.
 6. The device of claim1, wherein the spectrum processor is configured to encode the spectruminformation for transmission to the remote spectrum analysis unit. 7.The device of claim 1, further comprising a second receiver coupled tothe antenna in parallel with the first receiver.
 8. The device of claim7, wherein the second receiver is coupled to the spectrum processor. 9.The device of claim 1, wherein the antenna is a receiving antennaconfigured to receive a first radio frequency signal, wherein the devicefurther comprises a transmitting antenna configured to transmit a secondradio frequency signal.
 10. A wireless radio device configured towirelessly receive and transmit radio frequency signals in an operatingband, the device comprising: an antenna; a first receiver coupled to theantenna by a first receiving path for receiving a radio frequency signalfrom the antenna; a second receiving path in parallel with the firstreceiving path, the second receiving path coupled to the antenna andconnected to a spectrum analyzer, wherein the spectrum analyzer isconfigured to continuously scan the operating band while the firstreceiver receives the radio frequency signal and to record spectruminformation on the operating band; and a spectrum processor coupled tothe spectrum analyzer and configured to encode the spectrum informationand geographic information about the location of the device along withthe spectrum information for transmission to a remote spectrum analysisunit.
 11. The device of claim 1, wherein the spectrum processor isconfigured to encode the geographic information with the spectruminformation.
 12. The device of claim 1, further comprising a firsttransmitter coupled to the antenna for transmitting radio frequencysignals from the antenna.
 13. The device of claim 1, further comprisinga high selectivity receiver in the first receiving path configured toselect an operational frequency for the first receiver from within theoperating band.
 14. The device of claim 1, wherein the first receiver ispart of a transceiver comprising both a transmitter and a receiver. 15.The device of claim 1, wherein the first receiver operates independentlyof the spectrum analyzer.
 16. The device of claim 1, wherein thespectrum processor comprises a memory configured to store spectruminformation for later transmission.
 17. The device of claim 1, whereinthe spectrum processor is configured to encode the spectrum information.18. A wireless radio device configured to wirelessly receive andtransmit radio frequency signals in an operating band, the devicecomprising: an antenna; a first receiver coupled to the antenna by afirst receiving path for receiving a first radio frequency signal withinthe operating band from the antenna; a second receiver coupled to theantenna by a second receiving path for receiving a second radiofrequency signal within the operating band from the antenna; a spectrumanalyzer configured to continuously scan through the operating band andcollect spectrum information on the operating band concurrent with thefirst receiver receiving the radio frequency signal; and a transmittercoupled to the spectrum analyzer and configured to wirelessly transmitthe spectrum information and geographic location information to a remotespectrum analysis unit.
 19. The device of claim 18, wherein the firstreceiver is configured to operate at least partially independently ofthe secondary receiver, the spectrum analyzer and the spectrumprocessor.
 20. The device of claim 18, wherein the spectrum analyzer isconfigured to minimize interference at a predetermined frequency.